2.4A vs 2.26B vs 2.66B

lilkiller

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Feb 5, 2004
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Which of these cpus would be the best? Will each of them work in the same motherboard? I don't think that I will be able to overclock them since 1 of them is going into a Dell. I saw that the 2.4A has 1mb L2 cache while the 2.66B has 512kb L2 cache. Is the 2.4A better than the 2.66B?
 

Geomagick

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Dec 3, 1999
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Are you sure it's a 2.4A, this chip only had 512K L2 cache. The only 'A' model to have 1M is the prescott based 2.8A which runs a 533FSB.

However assuming that the chip is actually a 2.4A with 512K then it has a 400FSB and will work is pretty much any P4 board.

The 2.66 will run in any board with a 533FSB so look for any chipset from 845 onwards.

As for overclocking I don't have any experience with either of these chips.
 

Stormgiant

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Oct 25, 1999
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No, the 2.4A is a Prescott with 1Mb cache and 533fsb.

Given those 3 to choose, i would go with 2.4A if the board suport it, cause none of those have HT and the Prescott with the 1Mb cache will be faster, especially if overclock.
 

lilkiller

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Feb 5, 2004
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Will the 2.4A run in my board? I Have a 2.26B in it right now. They both look to be socket 478.
 
Sep 6, 2004
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Is the 2.4A better than the 2.66B?

NO!
The 2.4A is a prescott. They are not as efficient, clock for clock, as the northwood core (especially at lower speeds). That means that if you had a 2.4B, it would be better than the 2.4A. Since you've got a 2.66B you're way better off with that one.
 

LTC8K6

Lifer
Mar 10, 2004
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Well, the Prescotts excel at media encoding and are faster than Northwoods for that purpose. Overall, I'd say you'll see little difference between the three of them.

If you forced me to choose, I'd take the Prescott if it would work in the board, the 2.66B otherwise.
 
Sep 6, 2004
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NO YUO!

WHere do you get this from?
Here's anandtech's review of the prescott:
http://www.anandtech.com/cpuch...oc.aspx?i=1965&p=1
It compares the 800fsb hyperthreaded prescott with the northwood 800fsb hyperthreaded.
Now, the 533fsb prescott without hyperthreading should be LESS comparable with a northwood 533fsb without hyperthreading.
That prescott will actually become MORE efficient per clock than northwood at a certain point as clock speed increases. Unfortunately, it actually gets less so as it decreases. It pays a heavier penlaty for the lower speed FSB than northwood as its longer pipeline relies on high memory bandwidth and larger cache for the same performance with mis-predicts. This is why it needs double the L2 cache for roughly equivellent performance.
In other words, these aren't going to be comparable as the faster chips are.
The northwood will be signifigantly faster in nearly all tasks including media encoding which was already close as you can read from that review.
 
Sep 6, 2004
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forgot to add that it will draw more power and produce far more heat than the northwood which, aside from being more efficient is also clocked higher and doesn't suffer as large a penalty for the slower FSB.
 

LTC8K6

Lifer
Mar 10, 2004
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The Prescott draws only a little more power and is only a little warmer than Northwood. Nothing a good mobo and HSF can't handle easily. My opinion remains the same.

Note that in your link, the Prescott handily beat the P4C and even the P4EE in media encoding.

Prescott has some tweaks and SSE3 also, which may come in handy in the future. Or not. :D
 
Sep 6, 2004
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Handily is an exaggeration. Also, the northwood in this real world choice is running faster AND the prescott performs more poorly relative to northwood as clock speed decreases and better as it increases. Since this is a low Mhz chip, that's a bad thing. And, of course, you fail to note the MAJORITY of the benchmarks where the precot loses. With this real world hardware, I'm sure it would lose them all.

You statement that the prescot draws only a little more power and puts out a little more heat is incorrect. What the HECK are you basing that on?

Here are the real numbers based on the closest clock speed listed. It will be the same voltage and thus very similar. 70 compared to 100 is not just a little. These figures are maximum thermal power, not the bogus TDP numbers Intel churns out.
Northwood
49.8A * 1.40538V = 69.987924W
Prescot
78.0A * 1.28690V = 100.37820W



http://www.cpuheat.wz.cz/html/IntelPowerConsumption.htm
 

lilkiller

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Feb 5, 2004
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From the looks of this I think I'll be using the 2.66B as dell computers don't have the greatest cooling.
 

LTC8K6

Lifer
Mar 10, 2004
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To each his own. I stand by what I have said, based on real world reports here at anandtech by people who actually own Prescotts.

Prescotts overclock well, even on air, they are not much warmer than Northwood, and they are faster at media encoding than Northwood.

There is no reason not to buy a Prescott, unless a Northwood is cheaper, imo. Certainly not because Prescotts are "too hot", which they aren't.

Since Dell is using Prescotts, they must not be too hot to put in a Dell. Whether the mobo in question supports it, I cannot say.
 

lilkiller

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Feb 5, 2004
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What is the deciding factor of what a motherboard supports? I know socket type has to be the same. Is the only other factor FSB or is there something else?
 

LTC8K6

Lifer
Mar 10, 2004
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Well, it's likely that if the board isn't fairly new, it won't support the Prescott anyway. That's why I qualified my selection of the Prescott.

There are so many variables with different boards and chipsets and BIOSes that it's best to try to go to the board mfg's site to find out what CPU's are supported by a particular board and BIOS version.

Dell ought to be able to tell you the fastest CPU the Dell box will support. There is usually a Dell service tag number on the computer that you can enter at Dell's site.

You could always buy an A64 rig and beat all of the P4's. :D
 

lilkiller

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Feb 5, 2004
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I think my board only supports B type processors :(. I would upgrade the motherboard to a new board that supports overclocking and other stuff but I don't know if dell uses standard ATX or not. Do you know if its possible to replace the motherboard?
 

LTC8K6

Lifer
Mar 10, 2004
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It depends on the age and the model. Do you know the Dell model# or the service tag#? Do you know what chip is/was in the Dell?
 

user1234

Banned
Jul 11, 2004
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Is there any difference in the core overclocking potential of northwood vs prescot ? For example, comparing a pentium 4 2.4A (prescot) to 2.4B (Northwood), both default to a 133MHz x 18, is one of the more likely than the other to reach a higher speed, if we start increasing the FSB ?

A related question is if there's a difference in overclocking potential of cpu's with different clock multiples, for example Northwood 2.2 (133x17), and Northwood 2.4B (133x18) ? I mean, is the 2.26 likely to max out at lower speed than the 2.4B (for example 3GHz vs 3.3 GHz ) ?
 

Vee

Senior member
Jun 18, 2004
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Originally posted by: Stormgiant
No, the 2.4A is a Prescott with 1Mb cache and 533fsb.

- Can't understand why Intel need to confuse designations so. :|
 

user1234

Banned
Jul 11, 2004
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I'm trying to decide between the P4 2.26, 2.4A and 2.4B which are relatively cheap at $115-$135. They all have a 133/533 FSB which should allow me to overclock using standard PC2700 or PC3200, to get the FSB to 166MHz and hopefully even to 200MHz. My question is which of these CPUs would have the best overclocking potential. It seems like the Northwoods (2.26, 2.4B) hava a small performance advantage over Prescott (2.4A), but the prescott 2.4A has been proclaimed by HardOCP article to overclock well beyond 3GHz on air cooling, and possibly up to 3.7GHz using exotic cooling. I would like to konw if any of the two Northwood P4 I'm considering will allow me to do the same. Which would you choose (and why ) ?